arch/microblaze/lib/memset.c

   1 /*
   2  * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
   3  * Copyright (C) 2008-2009 PetaLogix
   4  * Copyright (C) 2007 John Williams
   5  *
   6  * Reasonably optimised generic C-code for memset on Microblaze
   7  * This is generic C code to do efficient, alignment-aware memcpy.
   8  *
   9  * It is based on demo code originally Copyright 2001 by Intel Corp, taken from
  10  * http://www.embedded.com/showArticle.jhtml?articleID=19205567
  11  *
  12  * Attempts were made, unsuccessfully, to contact the original
  13  * author of this code (Michael Morrow, Intel).  Below is the original
  14  * copyright notice.
  15  *
  16  * This software has been developed by Intel Corporation.
  17  * Intel specifically disclaims all warranties, express or
  18  * implied, and all liability, including consequential and
  19  * other indirect damages, for the use of this program, including
  20  * liability for infringement of any proprietary rights,
  21  * and including the warranties of merchantability and fitness
  22  * for a particular purpose. Intel does not assume any
  23  * responsibility for and errors which may appear in this program
  24  * not any responsibility to update it.
  25  */
  26
  27 #include <linux/types.h>
  28 #include <linux/stddef.h>
  29 #include <linux/compiler.h>
  30 #include <linux/module.h>
  31 #include <linux/string.h>
  32
  33 #ifdef __HAVE_ARCH_MEMSET
  34 void *memset(void *v_src, int c, __kernel_size_t n)
  35 {
  36         char *src = v_src;
  37 #ifdef CONFIG_OPT_LIB_FUNCTION
  38         uint32_t *i_src;
  39         uint32_t w32 = 0;
  40 #endif
  41         /* Truncate c to 8 bits */
  42         c = (c & 0xFF);
  43
  44 #ifdef CONFIG_OPT_LIB_FUNCTION
  45         if (unlikely(c)) {
  46                 /* Make a repeating word out of it */
  47                 w32 = c;
  48                 w32 |= w32 << 8;
  49                 w32 |= w32 << 16;
  50         }
  51
  52         if (likely(n >= 4)) {
  53                 /* Align the destination to a word boundary */
  54                 /* This is done in an endian independant manner */
  55                 switch ((unsigned) src & 3) {
  56                 case 1:
  57                         *src++ = c;
  58                         --n;
  59                 case 2:
  60                         *src++ = c;
  61                         --n;
  62                 case 3:
  63                         *src++ = c;
  64                         --n;
  65                 }
  66
  67                 i_src  = (void *)src;
  68
  69                 /* Do as many full-word copies as we can */
  70                 for (; n >= 4; n -= 4)
  71                         *i_src++ = w32;
  72
  73                 src  = (void *)i_src;
  74         }
  75 #endif
  76         /* Simple, byte oriented memset or the rest of count. */
  77         while (n--)
  78                 *src++ = c;
  79
  80         return v_src;
  81 }
  82 EXPORT_SYMBOL(memset);
  83 #endif /* __HAVE_ARCH_MEMSET */